Role of filament cross-section in properties of PET multifilament yarn and fabric. Part I: Effect of fibre cross-sectional shape on transmission behaviour of fabrics

The transmission property of a fabric is a key factor that affects clothing’s comfort and decides the functional potential of clothing. The dependence of filament cross-section with varying shape factor (SF) on air, moisture and thermal transmission behaviour of fabric is determined in case of polyester multifilament woven fabrics. The linear density of each filament is kept identical for all 12 cross-section shape filaments. The SF of filament cross-section is an important factor which remained the prime factor to influence the transmission behaviour of fabric samples directly in many cases. Other indirect factors that influence the transmission behaviour of fabrics when the SF is identical are yarn structure, inter-fibre and inter-yarn space. Twelve different novel cross-sectional shapes are considered to make the multifilament woven polyester fabrics. The fabrics made from multifilament yarns having different SFs show that relative moisture vapour permeability and air permeability decrease with the rise in SF. Wickability increases with the rise in the SF of a filament cross-section. Multilobal, hexalobal and plus shapes were made a part of novel cross-sectional shapes in order to develop fabrics of higher comfort index.     

New computer geometric modeling approach with filament assembly model for two-ply yarns structures

This article presents a new computer geometric modelling approach for three-dimensional of two-ply yarn structures with filament assembly model. The geometric of individual filaments in two-ply yarn structures with uncompressed and compressed states were studied. In the uncompressed state the filaments in ply yarns have the form of coaxial double wound helices; we simulate the paths of these filaments in the ply yarns. In the compressed state the transformation of the initial filament distribution from the uncompressed state into the distribution after compression by a transverse force. The ply yarns cross-section uses the concept of virtual locations to simulate the filament distributions. Each cross-section is rotated along the single yarn and the ply yarn length. The curve of each filament in each two successive cross-sections is approximated by NURBS and then each curve is created by sweeping a closed curve along the centerline of the single yarn and ply yarn path. The method described is demonstrated in the uncompressed and compressed state of two-ply yarns by the CAD model using geometric parameters of the double-rove acrylic-fiber yarns. The simulation using this approach can demonstrate more realistic and improved visual simulations of real two-ply yarns.     

弹力织物设计中有关问题的讨论

对弹力织物,尤其是弹力机织物设计中的有关问题进行了论述,包括芯比重和外包纱线的选择、织物紧度与密度要求等问题,并推导出氨纶弹力纱中氨纶丝含量的计算公式,有利于准确计算弹力织物设计中的纱号、织物中氨纶丝含量、织物紧度和重量等问题。     

平纹织物纱线截面形态经典理论探析及其泛化

平纹机织物内部纱线的截面一直被业界视为某种固定的形态,但应用可视化技术发现,基于经典的双凸截面模型存在问题,即使用微积分思路解决问题过程中,发现纱线截面变化的规律.研究结果表明,无论是单层机织物还是多层机织物,其纱线截面均呈现多元性,而非单一形态.特别是对于接结多层纬纱的经纱,其截面沿纱线长度方向按凹凸交变的规律呈周期性变化.这一研究成果对"织物纱线恒定截面论"提出了异议,对研究纱线的真实截面形态及织物外观模拟具有参考价值.     

Computer simulation of plain woven fabric appearance from yarn photographs

This article proposes a method for simulating plain woven fabric appearance based on photographs taken by still camera of actual yarns along their lengths. The survey mathematically models the transformation of yarns from a straight circular cylinder to a flattened and crimped form in the fabric structure. The simulation is performed by yarn images that are obtained by image processing techniques and resized according to mathematical models developed by means of the software prepared. Transforming circular yarn cross-section to elliptical one for simulating yarn flattening and modelling the crimped shape of yarn by an elastica curve are both convenient and realistic. The simulation of plain woven fabric can be performed by a method based on raster graphics. This article provides a model for yarn shape in fabric structure as well as a method for simulating plain woven fabric appearance. This method may be used in textile industry for design and quality control.     

网络环境下的机织物三维仿真模拟

为探索网络环境下的机织物三维仿真方法,建立了以圆形为纱线截面,三次B样条曲线为纱线路径中心线的织物空间几何模型;采用参数化设计方法,利用虚拟现实建模语言（VRML）和JAVA语言实现了网络环境下的机织物计算机三维模拟。上述方法生成的织物模拟图像文件体积小,通过Cortona等浏览插件即可实现网络发布,并能在网络环境下对三维模拟图像进行移动、旋转、缩放等操作,能在线交互输入纱线颜色及光照效果等材质属性,实时改变织物的模拟效果。为研究网络环境下的织物三维模拟提供了一种方法。     

Total porosity,theoretical analysis,and prediction of the air permeability of woven fabrics

Air permeability is one of the most important properties of textile materials that ensure their comfort. For many materials for technical applications (filters, sails, vacuum cleaners, parachutes, etc.), this is one of the main properties that determine their quality. The air permeability of woven textile fabrics depends on many parameters of fabric. Thus, the determination of air permeability of woven fabric is highly complex and difficult. In this study, we attempted to establish a theoretical model for the porosity and predicted the air permeability of woven fabrics. A theoretical model was created to predict the total porosity and the air permeability of a fabric structure depending on the geometrical parameters such as pore size, warp density, weft density, fabric thickness, number of yarn, diameter of yarn, and fiber density. For the purpose, a theoretical model of porous systems on D’Arcy’s law was used, and the validity of the model was confirmed by experimental results using 100% cotton and 97/3 cotton/lycra woven fabrics. Since the amount of air passing through both the pores between yarns and the interstices in the fibers constituting the yarn structure was calculated, theoretical values of air permeability were obtained very close to the experimental values.     

Mathematical model to predict vertical wicking behaviour. Part II: flow through woven fabric

The aim of the paper is to develop a mathematical model to predict vertical wicking behaviour of woven fabric. The first part of this series (Part I) has dealt with the mathematical model for predicting vertical wicking through yarn. In this part a model has been proposed to predict vertical wicking of the woven fabric, based on the developed yarn model. In order to model the flow through woven fabric along with the vertical flow through liquid carrying threads, the horizontal flow through transverse threads has also been taken into account. A simplified fabric geometrical concept (inclined tube geometry) and Peirce geometry for plain woven fabric have been used to define the fabric structure. Warp and weft linear density, fabric sett and yarn crimp have been considered in the fabric modelling. The theoretical wicking values of the yarn and fabric made from that yarn have been compared. Experimental verification of the model has been carried out using polyester and polypropylene fabrics. The model is found to predict the wicking height with time through the yarns and fabrics with reasonable accuracy.     

聚酯长丝/棉复合纱斜纹织物的保形性及服用性能

为研究聚酯(PET)长丝/棉复合纱斜纹织物的保形性及服用性能,利用PET长丝与纯棉纱开发了3种线密度为9.8 tex的纱线,并以二上二下斜纹组织织造了4种织物。对织物进行了折皱回复性、免烫性、尺寸稳定性、悬垂性等保形性能,强伸性、拉伸弹性、顶破性等抗变形性测试,以及手感风格、透湿性、透气性等服用性能测试。对比分析了纯棉纱织物与复合纱织物的保形性与服用性能。结果表明:PET长丝/棉复合纱可改善纯棉织物的折皱回复性、悬垂性,提高免烫等级,同时又不影响织物的服用性能;包芯纱织物比包缠纱织物有更好的保形性,更高的免烫等级,是免烫衬衫面料的理想选择。     

Visual aesthetic perception of handwoven cotton fabrics

We revealed the factors that govern the visual aesthetic perception of handwoven fabrics by performing two psychological experiments to determine the effects of cotton hand-spun yarn on the perceptual and cognitive responses to woven fabrics. First, a free sorting task followed by multidimensional scaling and hierarchical cluster analysis explored the effect of yarn type (hand-spun, machine-spun, and slub-yarn) on the woven fabric. Visual categorization of the fabrics depended on yarn type. Second, functional and aesthetic perceptions that produced the differences among yarn types were investigated by semantic differential scaling method that collected subjects’ ratings for the fabrics from 17 bipolar adjective pairs. Generalized linear mixed-effects modeling revealed the association between the yarn type and perception expressed by functional and aesthetic words. Visual aesthetic perception of fabrics was also affected by the consumers’ background. Our method and findings can be applied to examine the visual aesthetic of other textile products.     

应用纱线序列图像的电子织物构建

为检测纱线条干均匀性对织物外观的影响,在纱线条干图像测量的基础上,提出了一种基于纱线序列图像的电子织物的构建方法。通过建立织物组织变化模型和光照模型,将纱线直径值与基元组织点外观灰度纹理分布相结合,构建电子织物外观数学模型。实验中通过将采集的纱线序列图像进行图像分割和形态学运算等处理,获取纱线直径数据,代入到构建的织物外观数学模型中,实现基于纱线序列图像的电子织物的模拟并且相关参数可调。通过选择合理的织物结构参数,提出的电子织物模型能够真实的反映纱线条干均匀性对织物外观的影响,准确预测布面效果。     

产业用摩擦纺包芯纱性能研究

在DREFⅢ-摩擦纺机上生产涤纶短纤维包覆玻璃长丝作产业用包芯纱线,用于二维机织平纹织物及增强复合材料。通过摩擦纺包芯纱及其织物和复合材料与未经过包覆的玻璃长丝及其织物和复合材料的加工、拉伸张力、弯曲张力等性能的数据对比,来揭示摩擦纺包芯纱的性能特点。     

26—THE ELASTIC RESISTANCE TO BENDING OF PLAIN-WOVEN FABRICS

The elastic resistance to bending of woven fabrics has previously been considered in terms of the existence in the yarns of rigid and elastic sections. The difficulties inherent in such a model and the noticeable differences between the predicted and experimental findings are examined in this paper. Two models of a plain-woven fabric in which the yarn cross-sections are incompressible are then analysed theoretically to obtain the predicted relationship between the applied couple and the curvature of the fabric.

In the first model, the yarns are considered to be unset, i.e., if released from the fabric, they would be uncrimped, and in the second model they are considered to be completely set, i.e., if released from the fabric, they would retain all their crimp. The predicted bending resistance does not agree with the behaviour of actual fabrics owing to the difficulty of defining the ‘radius’ of the yarn in the fabric, but many puzzling qualitative aspects of the bending behaviour of woven fabrics are, as a result of the analysis given, satisfactorily explained.     

基于数字单元法的三维正交织物微观几何结构建模

为了反映织物内部纱线的空间构型和微观几何结构,针对在织物建模过程中,因忽略纤维间的相互作用而引起的纱线截面形状变化的问题,基于数字单元法理论,提出了一种计算纤维间摩擦力的方法。通过纱线纤维化离散,用数值模拟和仿真方法模拟三维正交织物成型过程,建立了5种精度递进的微观几何结构数值模型。5种模型中的每根纱线分别由4、7、12、19和37根数字纤维表征。研究结果表明:随着纱线纤维化离散程度的提高,仿真时间延长,织物厚度减小,纤维体积分数增大,节点平均作用力下降速度变缓,势能变小;当每根纱线由19根数字纤维组成时,所建织物的微观几何结构数值模型与真实织物样本在显微镜下的内部切片图像较为吻合。     

仿针织牛仔面料的开发及性能评价

为获得兼具针织和机织牛仔面料优点的新型牛仔面料,从纱线的选择、织造、后整理等方面探讨了仿针织牛仔面料的开发。对比测试了仿针织牛仔面料、针织牛仔面料、纯棉机织牛仔面料等5 种面料的拉伸断裂强力、撕破强力、色牢度等指标,并利用川端织物风格评价系统对牛仔面料的拉伸、剪切、弯曲、压缩、表面摩擦5 项指标进 行织物风格综合分析。结果表明,采用精梳纯棉纱作为经纱,涤纶长丝氨纶包芯纱作为纬纱,选择复合右斜纹组织,经特殊后整理工艺后生产的仿针织牛仔面料经向拉伸断裂强力高达685 N,撕破强力达59 N,粗犷挺括,柔软舒适,弹性和保型性俱佳,克服了针织牛仔面料和机织牛仔面料的风格缺陷。     

Surface roughness properties of polyester woven fabrics after abrasion

Effect of abrasion on surface roughness properties of textured polyester woven fabrics has been investigated. The effects of weft density, weft yarn filament number, fiber fineness, and weave pattern on surface roughness after abrasion were studied. Surface roughness values of control fabric (not abraded) and abraded fabrics after four different abrasion cycles were discussed according to different constructional parameters. Surface roughness values of fabrics changed according to abrasion cycles and the changes were related to yarn float lengths, yarn densities, yarn fiber fineness, and initial fabric surface roughness. A general overview of the results showed that abrasion eliminated the effect of texture especially at the fabric samples with initially high surface roughness. The surface roughness of fabrics with initially high surface roughness decreased at a greater extent than the ones with low surface roughness after abrasion. Fabrics with high surface roughness were affected more by abrasion and the effect of abrasion on rough surfaces depended on different manners regarding the compactness of woven structures.     

织物结构对热敏变色纤维织物呈色效果的影响

为了研究织物结构对热敏变色纤维织物呈色效果的影响,经纱采用棉纱,纬纱选用热敏变色粘胶长丝纱,设计织造了5种不同组织结构的机织物,对其变色前后的颜色空间值、三刺激值、彩度以及白度等颜色指标进行了测试,并分析了织物组织及纬密对热敏变色纤维织物呈色效果的影响及显著性。研究结果表明:织物组织对织物明度、彩度和色相偏红程度影响显著,对白度影响不显著。平纹织物的明度和白度最高,缎纹织物的彩度和色相偏红程度最高;织物纬密对明度影响显著,对彩度、白度、色相偏红程度影响不显著,随着纬密的增加,织物色相偏红程度呈增加趋势。研究结果对热敏变色纤维织物的设计开发具有一定的参考价值。     

不锈钢纤维/涤纶特种花式线及其电磁波屏蔽织物的开发

以不锈钢长丝和有色涤纶丝等为芯纱原料,纯棉纱线及彩色涤纶丝为饰纱原料,在HKV151B型花式捻线机上纺制出具有电磁波屏蔽特殊功能的23种花色的花式线;用SL7900剑杆小样织机进行小样试织,设计织制了10个规格系列的电磁波屏蔽功能织物小样。电磁屏蔽性能和常规性能测试的结果显示,花式线织物具有突出的抗电磁屏蔽性能,并可满足常规家用休闲防护服面料的基本服用性能和外观风格要求。     

Study of tensile properties of plain-woven fabrics in all-directional using energy method,Part II: experimental verification

Abstract

In the previous part of this series, ‘Comprehensive Tensile Modulus (CTM)’ was introduced as an important modulus to express the force-elongation behavior of plain-woven fabrics when the force is imposed on the fabric and extended it simultaneously in all directions. A theoretical model was presented to predict this modulus in the initial elastic region. In order to verify the accuracy of the model, a novel tensile test method was developed to measure load-extension curve of the fabric samples under the proposed loading condition. Thereafter, six plain-woven fabrics were produced with different raw materials and densities then were washed and dried to reach the relaxed state. Fabric samples were tested using the new method. The fabric’s experimental Comprehensive Tensile Modulus (CTMs) were determined from the results of the tests in all directions by the nine-point central difference method, and the calculated data were analyzed statistically to obtain the experimental CTM of fabrics. Reasonable agreement between theoretical and experimental results confirmed that the generated model is capable to predict the CTM index as a tensile property of plain-woven fabrics, adequately. The comparison between results of the theoretical model and experimental test shows that maximum error of prediction is 8.5% which is recorded for the grey fabric sample constructed from the OE Cotton yarn with nominal yarn count 24 Ne. Also, maximum experimental comprehensive tensile modulus (17.9 N/mm) is for the grey fabric sample constructed from the high tenacity continuous filament of Nylon with nominal yarn count 900den, in one millimeter extension with maximum modulus in warp and weft directions, that is, 5.6 N/mm and 6.6 N/mm in the same extension in the initial linear elastic region, respectively.